EXPERTS are predicting that in as little as 12 months' time our global supplies of oil will start to diminish. Demand will exceed supply, prices will rise, and suddenly all of the things we take for granted like commuting from Swansea to Cardiff, buying roses in February and holidaying abroad will be out of the question.

Having achieved a global economy which is dependent on mass production and the mobility of its work force, the change could render us back to a relative dark age where people live and work in small, self-sufficient communities.

A doomsday scenario? Not according to Patrick Holden, director of the Soil Association, which opened its annual conference in Cardiff yesterday.

The organisation is best known for its promotion and certification of organic food.

Pick up a bag of organic carrots or a tub of Green & Black's ice cream and you're likely to see the Soil Association stamp, guaranteeing your food has been produced in accordance with strict animal welfare and environmental standards.

But the message behind this conference is about more than just food.

The conference, titled One Planet Agriculture: Preparing for a post-peak oil food and farming future, aims to kick-start the discussion on what practical measures farmers, consumers and local communities can take to become less energy reliant.

The notion of One Planet Agriculture derives from a comment made by David Miliband at the 2006 Royal of England Show in which he laid down a challenge to farmers reflecting on the World Wide Fund for Nature's calculation that "we are living as if we had three planet's worth of resources to live with, rather than just one", and it's a challenge the Soil Association has embraced.

Mr Holden, who lives in Ceredigion, believes that while agriculture in the 20th century was about government-led, centralised systems of farming and food distribution, in the 21st century it will be defined by localism.

He says that, in hindsight, the fossil fuel era will be described as "a sort of extravaganza where we lived beyond our means, treating capital as income and squandered all this energy," but that things are now changing, and this year's conference is hoping to address that shift.

The academic term for all of this is peak oil, which refers to the point when the maximum amount of oil that can be extracted is reached, and production starts to tail off because reserves become more difficult, and consequently more expensive, to reach.

Experts can't say exactly when this will happen, but predict it will be sometime before 2010. While the world won't suddenly be without oil, environmentalists say rising prices will dramatically change the dynamics of cost effectiveness in transport, food production, housing and alternative energy sources. By 2021 it's estimated we will have just 50% of our current supply of oil, meaning we'll have been forced to change the way we live.

But there's also a cultural knock-on effect as well. If people aren't able to commute, they'll have to work close to home which means a return to the days of close-knit communities.

The concept sounds backward but the fact that this is the Soil Association's most over subscribed conference yet (organisers say they could have filled it twice over) and has attracted a host of high profile speakers (including editor of The Ecologist Zac Goldsmith, chef Hugh Fearnley-Whittingstall, presenter Jonathan Dimbleby and Welsh Assembly Government's Minister for Environment, Carwyn Jones), demonstrates how topics such as these are increasingly striking a chord with consumers and producers alike.

Instead of being a step backwards, Mr Holden insists it's a step in the right direction.

"It's not about looking backward but forward," he said. "It's not that we have to give up driving our cars tomorrow or totally transform our lifestyles but we have to bear in mind the more we can do in advance the better prepared we'll be for it," he said. "We have to start imagining a life post fossil fuel. It will happen before the end of the 21st century and it will start to affect us much earlier than that.

"It will take 10 years to begin to prepare the infrastructure so we need to start preparing now.

"I'm not preaching doom and despair, this isn't Big Bang. At the moment we are a world driven by oil which takes economic prosperity and mobility for granted but if the changes we make end up improving the quality of our lives that will be more than adequate compensation for what we lose out of in terms of GDP and mobility.

"This is something which is going to come to dominate our lives over the coming decade."

You could argue that with climate change dominating the headlines, warnings about peak oil are unlikely to get much of a positive response. But Mr Holden argues peak oil is a crisis which empowers consumers because solutions can be sought at a local level.

He said, "Climate change is making headline news and I think many of us feel strongly disenfranchised by the enormity of the challenge. If we are really committed we can do things like reduce the amount of times we fly by easyJet or make sure we turn off our TVs but we feel it's a problem that only the Government can really solve. The truth is our conscience doesn't provoke us into taking action on climate change. But peak oil is already in the pipeline. It's the train coming towards us on the other line and it's going to affect us whether we like it or not. It's going to really hurt.

"After the peak oil year, every year each of us is going to have to manage on 3% less fossil fuel than we did the year before. By 2030 that's nearly half of what we are using now.

"We all know that we have to do something about climate change and peak oil is the sister of that. It's going to affect our lifestyles, our businesses, our food supply.

"You can see how telling people about it could make them even more depressed, another disaster on its way but, strangely, I find it's quite inspirational, that people can take action against it.

"It makes business and planetary sense to try to reduce your carbon footprint especially when it can mean an improved quality of life."

Understandably, the idea of such a transition isn't likely to be popular with everyone. But Wales' Environment Minister Carwyn Jones is enthusiastic about the idea. Having championed sustainable food production in Wales he believes buying not just organic food but locally grown organic food is the key to the future and with developments in new technology, he says a move towards a more local life wouldn't be detrimental to Wales' economy.

He said, "Now that more and more people are online, it's possible for people to work from home. The translators at the Assembly are based all around Wales, some even in Patagonia. You don't have to be in Cardiff to do that work.

"And because of that it means people don't have to move out of rural communities in the way that they used to."

The idea of peak oil is proving popular with a new breed of green celebrities - this week's conference started off with an organic fashion show compered by Zac Goldsmith, and starring celebrity models.

But the nature of this challenge is decidedly local. Which means whether it succeeds or fails rests solely on those on the ground.

The key, according to Rob Hopkins, is that we see peak oil as giving us the chance to make a positive change, not a negative one. Mr Hopkins, who is also speaking at the conference, has pioneered a concept of Transition Towns - towns which have agreed to prepare for a peak oil future by creating locally based, self-reliant communities.

Having experimented with the idea in Kinsale, Ireland, where he drew up an action plan for timetabling how the town could reduce its energy consumption, Mr Hopkins has gone onto pioneer the idea in a number of towns across the UK.

Next on the list could be Lampeter, where environmentalists have arranged a public meeting in April to discuss the possibility of adopting a similar action plan.

The guiding principle behind these towns is that a future without oil and gas could, if sufficient imaginative preparation is put in place, be a better place than the present, with a higher quality of life.

Mr Hopkins said, "I think when you put peak oil and climate change together, it's going to provoke the most immense change and shift in how we do everything. You can't engage people if you see it as a hardship.

"We have been trying to say, this is the great adventure of our time, if we can get it right it will be a historic transition.

"I think people are becoming very aware of climate change and peak oil.

"It's something that is very easy to feel despondent about but the only way we will solve any of these things is through creativity and engaging in this as an exciting transition."